The invention relates to a coil unit of a linear motor with electromagnetic coils, having at least one iron core and having a housing which encloses said coils and iron core and which is open toward a magnetic track of the linear motor, with the iron core being permanently linked with the housing, the coils being secured in position by means of a cast compound and at least one cooling-air channel being provided within the housing.
A coil unit of said type is known from, for instance, DE 19842384 A1. According to this, a primary motor section is accommodated in a housing called a bogie truck and is able to travel over a secondary section of a rail-type guide housing. A primary section of said type customarily consists of a magnetic iron core which can be actuated by means of transverse coils. It is customary for coils of said type to be cast-sealed with the core and housing and thereby secured in position. Embodied in the housing according to column 3, rows 23 to 26 are ventilation slots intended to dissipate the motor's heat loss and minimize heating of the coil section.
A double-acting linear motor is furthermore known from U.S. Pat. No. 4,172,229 A wherein an iron core is inserted between the side flanges of a U-shaped magnetic section. The iron core is wound round with coils in whose spaces are located forced-ventilated cooling-air channels. Said cooling-air channels increase the distance between the coils, thereby increasing the pitch width between the active linear motor sections.
A linear motor is furthermore known from U.S. Pat. No. 5,642,013 A wherein the coil windings are set into slot-type recesses in the magnetic core. In their base area said recesses accommodate cooling tubes for a cooling fluid which has to be channeled in via a pressure pipe and channeled away via a return pipe. Pipe connections of this type are unsuitable for fast-moving coil sections of the kind used, for instance, for equipping substrates with electrical components. The cooling channels furthermore have a detrimental effect on the magnetic flux.